1. Technical Field
The present disclosure disclosed a light emitting diode array structure and its fabricating method thereof.
2. Description of the Related Art
The light radiation theory of light emitting diode (LED) is when electrons move between an n-type semiconductor and a p-type semiconductor, the electron energy difference caused by different band energy between the n and p type semiconductors is released and accompanied by generation of photons. Because the light radiation theory of LED is different from the incandescent light which is through the heating of filament, the LED is also called a “cold” light source. Moreover, the LED is also more sustainable, longevous, light and handy, and less power-consumption, therefore it is considered a new generation product in the lighting markets.
FIG. 1 illustrates the structure of a conventional light emitting array, which includes a sapphire substrate 101, a plurality of light emitting stacks 100 formed above the sapphire substrate 101, and a buffer layer formed between the sapphire substrate 101 and the light emitting stack 100 optionally. Each light emitting stack 100 comprises an n-type semiconductor layer 103, an active layer 104, and a p-type semiconductor layer 105. Because the sapphire substrate 101 is not conductive, the plurality of light emitting stacks 100 is divided by the trenches etched from the light emitting stack 100 to the sapphire substrate 101 and covered by an insulating layer 108. Besides, partial of the plurality of the light emitting stacks 100 is etched to expose the n-type semiconductor layer 103. A first connecting electrode 106 and a second connecting electrode 107 are formed on the exposed n-type semiconductor layer 103 and the p-type semiconductor layer 105. The plurality of light emitting stacks 100 is parallely connected through wires 109, the first connecting electrode 106 and the second connecting electrode 107.
The parallely connected structure as illustrated in FIG. 1 is a horizontal electrical structure wherein the wires are electrically connected on the same side of the substrate and the current passes the semiconductor layer laterally. But because of the poor lateral conductivity of the p-type semiconductor is poor, the structure turns to be an n-side up structure. To form the n-side up structure, the sapphire substrate should be polished or lift-off by laser which damages the electrical connection and makes the fabricating process complicated.